Electrophysiological correlates of facial decision: Insights from upright and upside-down Mooney-face perception

Abstract

We investigated the ERP correlates of the subjective perception of upright and upside-down ambiguous pictures as faces using two-tone Mooney stimuli in an explicit facial decision task (deciding whether a face is perceived or not in the display). The difficulty in perceiving upside-down Mooneys as faces was reflected by both lower rates of "face" responses and delayed "face" reaction times for upside-down relative to upright stimuli. The N170 was larger for the stimuli reported as "faces". It was also larger for the upright than the upsidedown stimuli only when they were reported as faces. Furthermore, facial decision as well as stimulus orientation effects spread from 140-190 ms to 390-440 ms. The behavioural delay in 'face' responses to upside-down stimuli was reflected in ERPs by later effect of facial decision for upside-down relative to upright Mooneys over occipito-temporal electrodes.Moreover, an orientation effect was observed only for the stimuli reported as faces; it yielded a marked hemispheric asymmetry, lasting from 140-190 ms to 390-440 ms post-stimulus onset in the left hemisphere, and from 340-390 to 390-440 ms only in the right hemisphere.Taken together the results supported a preferential involvement of the right hemisphere in the detection of faces, whatever their orientation. By contrast, the early orientation effect in the left hemisphere suggested that upside-down Mooney stimuli were processed as non face objects until facial decision was reached in this hemisphere. The present data show that face perception involves not only spatially but also temporally distributed activities in occipitotemporal regions.

The early development of face processing — What makes faces special?

“…N170 amplitude is also larger in response to Mooney faces (high-contrast two-tone pictures of faces only depicting shadow versus light information, see Fig. 3) that are consciously perceived as faces versus Mooney faces that are not perceived as faces, suggesting that the identification of a stimulus as a face is related to the N170 response [72] , though there is also evidence that the N170 can be elicited in response to unconsciously perceived faces in patients with neglect [73] .…”

A new Mooney test

“…The N170 component of the event-related potential, which occurs specifically in response to the image of a face (Bentin, Allison, Puce, Perez, & McCarthy, 1996), is also observed in response to the presentation of Mooney faces; and when the Mooney face is consciously perceived, the amplitude of this component is increased (George, Jemel, Fiori, Chaby, & Renault, 2005;Jeffreys, 1989;Jemel, Pisani, Calabria, Crommelinck, & Bruyer, 2003;Latinus & Taylor, 2005). Furthermore, the highly face-selective fusiform face area shows increased activity upon the conscious perception of a Mooney face, as compared to the failure to perceive it (Andrews & Schluppeck, 2004;Kanwisher et al, 1998;Rossion, Dricot, Goebel, & Busigny, 2011).…”

Species sensitivity of early face and eye processing

“…A host of studies have shown the strong sensitivity of N170 to human faces, as reflected by larger amplitude to faces than a variety of objects (Bentin et al, 1996;Eimer, 2000;Itier et al, 2006;Rossion et al, 1999), whether the stimulus is a schematic, sketch, painting, drawing or photograph of a human face (Sagiv and Bentin, 2001), or a twotone Mooney figure perceived as a face (George et al, 2005;Latinus and Taylor, 2005). The N170 is generally viewed as a marker of the encoding stage of the face structure (Eimer, 2000;Rossion et al, 1999), when the perceptual representation of a face is being created, although its sensitivity to identity is still actively debated (e.g.…”